The Iraqi government will investigate how the hanging of Saddam Hussein came to be filmed and images of his death broadcast around the world, it was announced today.

The showing of footage of Saddam's last moments has been widely condemned, and is feared likely to further inflame tensions in an already volatile situation.

Film of the former Iraqi president's execution on Saturday lasts for two and a half minutes and is thought to have been filmed on a mobile phone.

It shows him being taunted by prison officials, who tell him to "go to hell", and chant the name "Moqtada", a reference to Moqtada al-Sadr, the Shia cleric and leader of the Mahdi army militia. Saddam seems to respond by sarcastically repeating Mr Sadr's name.

An aide to the Iraqi prime minister, Nuri al-Maliki, said the government was investigating how Saddam had been filmed on the gallows, turning his execution into a televised spectacle.

Reuters reported that Khudayer al-Khuzai said it appeared some guards had violated instructions not to bring mobile phones or cameras.

"The Iraqi government is going to have an investigation into what happened," Mr Khuzai is quoted as saying.

"This operation should be done with the highest standards of discipline and with respect for the condemned man, both when he's alive and once he's dead. Anything that did not meet those standards should be accounted for."

A film released earlier to Iraqi television stopped short of showing Saddam's death, but the latest footage - which is on video-sharing websites such as YouTube - shows his death.

It reveals that the trapdoor beneath his feet was opened as he was in the middle of praying - likely to further enrage his supporters.

Sunni Muslims today gathered to show their anger and grief over Saddam's death.

Earlier today, John Prescott condemned the video during an interview on BBC Radio 4's Today programme.

"Frankly, to get the kind of recorded messages coming out is totally unacceptable," he said. "I think whoever's involved and responsible for it should be ashamed of themselves."